Various heat exchangers are mounted on vehicles such as motor vehicles. To obtain a comfortable space in motor vehicles, an enlarged passenger compartment must be made available, with the inevitable result that the space usable for installing a heat exchanger or like component becomes limited. For this reason, a reduced size and a smaller weight are required of heat exchangers, while a simplified procedure is needed also for installing the heat exchanger in motor vehicles.
In order to fulfill these requirements, heat exchangers of the unit type are known which comprise, for example, a condenser for motor vehicle air conditioners and an oil cooler which are assembled into a unit (see, for example, JP, U No. 6-4218 and JP, A No. 9-152296). The oil cooler is used for cooling an oil for use in the engine, power steering device, automatic transmission or the like.
The unit-type heat exchanger disclosed in JP, U No. 6-4218 comprises two pipelike headers arranged in parallel to each other at a spacing, a plurality of parallel heat exchange tubes joined at opposite ends thereof to the headers, and a partition plate provided in each of the headers for dividing the interior of the header into a condenser header portion and an oil cooler header portion. The partition plate is inserted into the header through an insertion hole formed in the peripheral wall of the header and brazed to the header.
However, if the unit-type heat exchanger has a faulty brazed joint between the partition plate and the header, there arises the problem that the oil of the oil cooler becomes mixed with the refrigerant of the condenser to impair the performance of the heat exchange cycle including the condenser, or that the refrigerant of the condenser becomes mixed with the oil of the oil cooler to adversely influence the performance of the device for which the oil is used.
The unit-type heat exchanger disclosed in JP, A No. 9-152296 comprises two pipelike headers arranged in parallel to each other at a spacing, a plurality of parallel heat exchange tubes each having opposite ends joined to the respective headers, and two partition plates arranged as spaced apart from each other in each of the headers and brazed to the header for dividing the interior of the header into a condenser header portion and an oil cooler header portion. The peripheral wall of each of the headers is provided with a monitoring hole at a portion thereof corresponding to the space between the two partition plates for discharging therethrough a fluid leaking through the partition plates to the outside of the header.
If the unit-type heat exchanger has a faulty brazed joint between the partition plate and the header, the oil leaking from the oil cooler or the refrigerant leaking from the condenser will be drained from the space through the monitoring hole, whereas the arrangement can not completely prevent the oil from becoming mixed with the refrigerant of the condenser or the refrigerant from becoming mixed with the oil of the oil cooler. Thus, the same problem as encountered with the unit-type heat exchanger disclosed in JP, U No. 6-4218 is also experienced. Moreover, water will ingress into the header through the monitoring hole and is therefore likely to render the header susceptible to corrosion.
An object of the present invention is to overcome the above problems and to provide a unit-type heat exchanger wherein fluids flowing through adjacent two heat exchange portions can be prevented from mixing.